Generally described, computing devices and communication networks can be utilized to exchange information. In a common application, a computing device can request content from another computing device via a communication network. For example, a user at a personal computing device can utilize a software browser application, typically referred to as a browser, to request a web page from a server computing device via the Internet. In such embodiments, the user's computing device can be referred to as a client computing device and the server computing device can be referred to as a content provider.
From the perspective of a user utilizing a client computing device, a user experience can be defined in terms of the performance and latencies associated with obtaining network content over a communication network, such as obtaining a web page, processing embedded resource identifiers, generating requests to obtain embedded resources, and rendering content on the client computing device. Latencies and performance limitations of any of the above processes may diminish the user experience. Latencies may arise based on network traffic, geographic distance between computing devices, the size and nature of the requested resources, etc. Network resources may be cached in an effort to reduce latencies and improve performance in response to subsequent requests for the cached resources.